 /*******************************************************************************
  * Copyright (c) 2005, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.osgi.framework.internal.core;

 import java.io.IOException ;
 import java.net.URL ;
 import java.util.Enumeration ;

 import org.osgi.service.packageadmin.ExportedPackage;
 import org.osgi.service.packageadmin.PackageAdmin;

 /**
  * Global policy is an implementation of a buddy policy. It is responsible
  * for looking up a class within the global set of exported classes. If multiple
  * version of the same package are exported in the system, the exported package
  * with the highest version will be returned.
  */
 public class GlobalPolicy implements IBuddyPolicy {
     private PackageAdmin admin;

     public GlobalPolicy(PackageAdmin admin) {
         this.admin = admin;
     }

     public Class loadClass(String name) {
         ExportedPackage pkg = admin.getExportedPackage(BundleLoader.getPackageName(name));
         if (pkg == null)
             return null;
         try {
             return pkg.getExportingBundle().loadClass(name);
         } catch (ClassNotFoundException e) {
             return null;
         }
     }

     public URL loadResource(String name) {
         //get all exported packages that match the resource's package
 ExportedPackage pkg = admin.getExportedPackage(BundleLoader.getResourcePackageName(name));
         if (pkg == null)
             return null;
         return pkg.getExportingBundle().getResource(name);
     }

     public Enumeration loadResources(String name) {
         //get all exported packages that match the resource's package
 ExportedPackage[] pkgs = admin.getExportedPackages(BundleLoader.getResourcePackageName(name));
         if (pkgs == null || pkgs.length == 0)
             return null;

         //get all matching resources for each package
 Enumeration results = null;
         for (int i = 0; i < pkgs.length; i++) {
             try {
                 results = BundleLoader.compoundEnumerations(results, pkgs[i].getExportingBundle().getResources(name));
             } catch (IOException e) {
                 //ignore IO problems and try next package
 }
         }

         return results;
     }
 }

